The present invention generally relates to a so-called multi-purpose batch plant. More particularly, the invention relates to a small-capacity multi-purpose batch plant to be used for producing the products, though in small amounts, of very high purity or without contamination.
For production of the products of high added values in relatively small amounts such as fine chemicals, an invented apparatus for carrying out this in one vessel under different conditions depending on the purpose of the production, includes various plants for batch processes, and some of them have been used.
Typical examples of known batch plants are disclosed in "Vessel for Batch Production" of Japanese Patent Disclosure No.62-144745 and "Movable Tank Apparatus" of Japanese Patent Disclosure No.02-198628. These apparatuses employ not the system of transferring the materials to be treated, but the system of transporting the vessels from a station to station so as to carry out sequential operations.
In some manufacturing processes, for example, those for producing fine chemicals, there are many processes which involve chemical reactions, particularly, repeated complicated reactions. Further, the reaction temperatures extend over such a wide range as from minus ten to three hundred and some ten degrees centigrades, and strict control of the temperature is required. In numerous cases, the same vessels are subjected to repeated heating and cooling. The problems common in these situations are as follows:
______________________________________ Heat Coldness Source Source Problems ______________________________________ 1 Steam Thermal Heating to 300.degree. C. or higher requires Media steam of 100 kg/cm.sup.2 or higher. Usual + jaket cannot stand with this pressure. Water Mixing of thermal media into water is inevitable. 2 Thermal Thermal Thermal media may pollute the Media Media environment. 3 Electric Cooling Local heating tends to occur. Cooling Heating Coil coil, if used, may be disturbance to the electric heating. ______________________________________
In case where the range of thermal difference is large, welded parts of jaketted vessels receive significant thermal stress. This stress could be absorbed by an expansion bellow, but the effect is limited. If a crack occurs between the vessel body and the jaket, then the thermal media will be contaminated inside the vessel.
Even if the vessel can stand with this kind of problems, in the system of transporting the vessels, it is necessary to attach and detach the pipings for the utilities to and from the vessels at every cycle of heating and cooling. In addition to this, the blowing out of the liquid in the vessel must be done; and thus, a significant amount of labor is required.
The above discussed system of transporting vessels is based on the avoidance of contamination by carrying out no transfer of the content between the vessels. This benefit is not, however, available in some cases. Namely, in case where two liquid phases are formed after the reaction, the lower phase is separated and only the separated liquid is used in the subsequent reaction, it is then to transfer the separated liquid to another vessel. Thus, if the transfer is done through pipings, the possibility of contamination in the pipings is high. Also, in the case where the liquid obtained by an operation such as reaction or dissolution in one vessel is used as a dropping liquid to the other vessel, as far as the vessels being placed in the same level, gravity cannot be used as the driving force for transferring and it is necessary to use a pump and pipes. If the vessels are in the different stages, dropping the liquid in the direction from an upper stage to a lower stage is possible, but impossible in the reverse direction.